In recent years, liquid crystal display devices are often used as flat panel displays in various fields. However, contrast and shade vary depending on viewing angles. A need for a light source such as a backlight hinders lower power consumption. Reduction in the thickness and weight of a liquid crystal display is limited. These serious problems still remain.
To address the problems, self-luminous organic EL display devices including organic EL elements are expected in place of liquid crystal displays. In an organic EL element, a current flows through organic EL layers sandwiched between an anode and a cathode so that organic molecules forming the organic EL layers emit light. Being self-luminous, organic EL display devices using such an organic EL element are thin, light, and low in power consumption. In addition, organic EL display devices provide a wide viewing angle, and thus draw great attention as a flat panel display in the next generation.
However, in general, after a certain period of drive, light-emitting characteristics, such as brightness and uniformity in light emission, of an organic EL element deteriorate significantly from the initial state. The deterioration in the light-emitting characteristics is attributed to deterioration of an organic layer due to moisture of outside air and oxygen, which has entered the organic EL element, or separation of the organic layer from an electrode due to moisture.
To address the problems, a technique of providing a sealing film to reduce entry of gas generated by, e.g., moisture is disclosed. More specifically, an organic EL display device has been disclosed which includes a plurality of light-emitting elements arranged above a substrate, an organic buffer layer covering the plurality of light-emitting elements; and a gas barrier layer covering the organic buffer layer, wherein the gas barrier layer has first inorganic films containing a silicon compound containing nitrogen and second inorganic films containing an oxide of a material for forming the first inorganic films. Such a configuration may provide an organic EL display device having a gas barrier layer with durability under stress (see, for example, Patent Document 1).